"Since Les Mis[érables] is coming back to Broadway, I thought maybe Jason and Neil might give us a little bit of the 'Confrontation,'" a student said to the actors.
The duo first performed this number from the hit muscial on the Megan Mullaly Show back in 2006.
"You haven't sung that in a long time!" Hannigan quipped.
After they quickly figured out who portrayed whom the first time around, the actors eased back into their respective roles and belted out the lyrics with complete and total conviction. And a little bit of comedic flair, too.
The cast and crew haven't been shy about sharing their emotions about the big finale. On Twitter, co-creator Craig Thomas said, "Saying bye to Ted, Barney, Robin, Lily and Marshall will be as hard as saying bye to real people in my life (sorry, real people in my life!)."
Hannigan tweeted a picture from the last How I Met Your Mother table read featuring a whole mess of wadded up tissues. "Umm...so this is how the last HIMYM Table Read went for me. #sorrytrees," she tweeted.
The series finale airs this Monday at 8 p.m. on CBS. Until then, enjoy this wonderful clip!
(E! Online and Inside the Actors Studio are part of the NBCUniversal family.)